BACKGROUND: Ruptured abdominal aortic aneurysm (rAAA) is associated with high mortality. Research suggests that statins may reduce abdominal aortic aneurysm (AAA) growth and improve rAAA outcomes. However, the clinical impact of statins remains uncertain in relation to both the risk and prognosis of rAAA. METHODS: This nationwide, population-based, combined case-control and follow-up study included all patients (aged at least 50 years) with a first-time hospital admission for rAAA and 1:1 matched AAA controls without rupture in Denmark from 1996 to 2008. Individual-level data on preadmission drug use, co-morbidities, socioeconomic markers, healthcare contacts and death were obtained from Danish nationwide registries. RESULTS: The study included 3584 cases and 3584 matched controls. Current statin use was registered for 418 patients with rAAA (11.7 per cent) and 539 AAA controls (15.0 per cent), corresponding to an age- and sex-matched odds ratio (OR) of 0.70 (95 per cent confidence interval (c.i.) 0.60 to 0.81) for rAAA in current statin users versus never users. The decreased risk of rAAA remained after adjustment for potential confounding factors (adjusted OR 0.73, 0.61 to 0.86). The overall 30-day mortality rate from time of hospital admission among patients with rAAA was 46.1 per cent in current statin users compared with 59.3 per cent in never users (adjusted mortality rate ratio (MRR) 0.80, 95 per cent c.i. 0.68 to 0.95). Patients who had formerly used statins did not have reduced mortality (adjusted MRR 0.98, 0.78 to 1.22). CONCLUSION: Statin use was associated with a reduced risk of rAAA and lower case fatality following rAAA. These results support current guidelines that recommend statin therapy in patients diagnosed with AAA.